Configuring SQUID to be CCPROXY

My ISP allows only one computer to have an internet connection. To restrict other computers to be used, the MAC address of my network card has to be registered with them, and I can only use internet from that particular computer. In windows, I can share this internet connection with other computers of my home through a program called CCProxy. In the computer which is connected to the ISP (Hence forth referred to the Host), has two NICs. One has it's MAC address registered to my ISP. Another one is connected to a Wifi router. CCProxy acts as a proxy server, and it allows other computers in my LAN to connect through the Host's internet connection. In the hosts, we put proxy settings in browser's option page. Say host's IP is 192.168.0.2; then the proxy settings would be the IP of the host, and the ports for HTTP proxy 808, HTTPS 808, SOCKS5 1080 and FTP 2121. By this I can visit most websites though LAN. Only problem is I have to keep my host on as long as I want to browse other pages.

Now Problem with CCProxy is that it does not allow more than 3 computers to connect to internet by the trial version. I heard a similar opensource project called SQUID. Problem is squid is possibly not that userfriendly, and designed perhaps for performance. Can any one help me configure any linux based proxy software (SQUID or others) that would have the exact same functionality as CCProxy. i.e.

Host is connected to internet
Host has two NICs
the local NIC connects other PCs via router / Hub / Switch
The host acts as a proxy server to all other machines in LAN with the following proxy settings:

For one thing, I bought a TPLink router that has MAC cloning capability. The router can connect to the remote host fine. But as I try to connect to any website through a computer connected to router via DHCP, I cannot. I can ping the router's external IP and the default gateway of my ISP through the computer. If I keep same MAC address in my PC as before, I can ping the DNS ip address, but cannot access any websites. ping www.google.com resolves to some IP address. If I use different MAC, I cannot ping the DNS server too.